When injecting an HTML base element, some requests would ignore the CSP's base-uri settings and accept the injected element's base instead. This vulnerability affects Firefox ESR < 102.3, Thunderbird < 102.3, and Firefox < 105.
https://www.mozilla.org/security/advisories/mfsa2022-42/
https://www.mozilla.org/security/advisories/mfsa2022-41/